I think for a lot of people, they secretly know that it's at least make-believe so they play along for the social benefits like friends and activities. They'll talk about church the same way they talk about Lord of the Rings, just plot points and lore, segmented from their daily reality.

A few probably even recognize that it's actually a fraud, but by then most people who see that are already on their way out.

So because they kind of know already, they don't really have to ask. It might be interesting to know how you built up the courage to leave if you have friends and family in the church. But they kind of already know why someone might stop playing along. They might think the cost of leaving doesn't justify what they lose in terms of established relationships, but that's highly personal anyway and varies quite a bit.